Electric heating apparatus



W. B. SMITS.

ELECTRIC HEATING APPARATUS.

APPLICATION FILED HAH. I, i920.

1,414,226. man@ Apr. 25, 1922 rrvRA/EK- v Heating Apparatus, of `whichthe following 4tirarsi) STATES PATENT oFFicE.

wnrmsn BENE SMITS, or DILMEN, NETHERLANDS.

i ELECTRIC HEATING APEARATUS.

Specification of Letters Patent. Patnted Apr, 25, 1922- Application ledMarch 1, 1920. Serial No. 362,516.

10 all w hom t may concern:

Be it known that l, WiJTsE BnrJn SMrrs, subject of the Netherlands, andresident of Dilmen, Netherlands, have invented certain new and usefulImprovements in Electric is a specification. i V

Electric heating bodies are. already known that are composed of aheath-refractory insu-f lating body for receiving the resistances, andof a metal casing which encloses the whole and which is` formed bycasting metal around the insulating body. y

f 'Heating bodies of that kind have however a low eiiiciency because theinsulating bodyl hinders very considerably the radiation of the heat.Moreover the material cast around the heating elements has a lowerco-eiicient of expansion than the inner core. Sincewthe core is far moreheated by the intermediate insulating body thanthe casing, the entireheating body is liable to burst asunder.

Also, after use, owing to the more rapid coolnately with the clampingplates, in a metal casing in which `they can be fixed for instancevbymeans of wedges. The core thus produced is enclosed in a casing which iscast around it and which is formed of a material which is a good heatconductor and which has a higher coefficient of eXpansion than that ofthe material of which the clamping plates are composed. f

If the clamping plates and the casing are made for instance of copper,then aluminium for example may be used as the surrounding material. Incooling, the aluminium f form of a shrinks to a greater extent than thecopper and thus presses the heating cores very tightly together. In theaccompanying drawing, Figure l 1s a section in line c-d of Figure 2 ofone embodiment of my invention and Figure 2 isa section on linea-`b ofFigure 1.

In, the drawings, numeral 1 indicates the plates of coppery lforinstance, which are wedge shaped at their ends, while 2 indicates'v Thelatter are pref-` the resistance elements. erably of wire between micaplates. The

'alternate platesl and elements are held in alinement by bolts 3. Thewhole isV surrrtiunded by the aluminum case indicated a 4.

The current conducting wires are diagrammatically shown in Figure 2.

By varying `the shape of the cores an apparatus constructed in thismanner can be used for very different purposes. When made in block shapeit can be employed as a dipping apparatus, or in combination withV acopper body as a soldering bit. In the plate it can be used as thebottom of a boiler. i

In' this manner also it is possible to cast resistance wires which areprovided for instance with a coating of enamel, directly in the form ofrods orbars which can be used as curling tongs, medical instruments,electric furnaces and the like. The electric insulating material isprotected on all sides by the surrounding material, thus preventing thepossibility of the enamel coating breaking. Y

The main advantages of the improved heating apparatus made in thismanner are the following:

1. The complete exclusion of oxygen, whereby great durability is ensuredeven under a very high load;

2. Direct contact with the covering, that is to say, a good transfer ofthe heat;

3. VVatertightness, and consequently the prevention of short-circuitingdue to moisture;

4. Great mechanical strength, especially when dropped, because nothingcan become loose inside the apparatus.

Having now particularly described andA ascertained the nature of my Saidinvention and in what manner the same is to be performed, I declare thatwhat I claim is:-

An electric heater, comprising a core com posed of resistance elementsand clamping plates arranged in alternation., and a coating ofheatonducting material enclosing said core, said heat-conductingmaterial having a higher coeicient of expansion than the material ofwhich the clamping plates are 10 constructed.

Signed ,'`\1nsterda1n, Netherlands, this 6th dag7 oit February, 1920.

VIJTSE BEIJE SMITS.

vilfvitnesses M. AUARACH, T. A. YI-IANGENODYK.

